Merge commit 'd803bfe2b1fe7f5e219e50ac20d6801a0a58ac75' as 'vendor/ruvector'

vendor/ruvector/crates/prime-radiant/src/cohomology/mod.rs

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+//! Sheaf Cohomology Module for Prime-Radiant
+//!
+//! This module implements sheaf cohomology computations for detecting global
+//! inconsistencies (obstructions) in the coherence graph. Sheaf cohomology
+//! provides powerful tools for understanding when local consistency cannot
+//! be extended to global consistency.
+//!
+//! # Mathematical Background
+//!
+//! For a sheaf F on a graph G, the cohomology groups H^n(G, F) measure
+//! obstructions to extending local sections to global ones:
+//!
+//! - **H^0(G, F)**: Global sections (globally consistent assignments)
+//! - **H^1(G, F)**: First cohomology (obstructions to patching local data)
+//!
+//! The key computational tool is the **coboundary operator** delta:
+//! ```text
+//! delta^0: C^0(G, F) -> C^1(G, F)
+//! (delta^0 f)(e) = rho_t(f(t(e))) - rho_s(f(s(e)))
+//! ```
+//!
+//! where rho_s, rho_t are the restriction maps on edge e.
+//!
+//! # Sheaf Laplacian
+//!
+//! The **sheaf Laplacian** L = delta^T delta generalizes the graph Laplacian:
+//! ```text
+//! L_F = sum_e w_e (rho_s - rho_t)^T (rho_s - rho_t)
+//! ```
+//!
+//! Its spectrum reveals global structure:
+//! - Zero eigenvalues correspond to cohomology classes
+//! - Small eigenvalues indicate near-obstructions
+//!
+//! # References
+//!
+//! 1. Hansen, J., & Ghrist, R. (2019). "Toward a spectral theory of cellular sheaves."
+//! 2. Robinson, M. (2014). "Topological Signal Processing."
+//! 3. Curry, J. (2014). "Sheaves, Cosheaves, and Applications."
+
+mod cocycle;
+mod cohomology_group;
+mod diffusion;
+mod laplacian;
+mod neural;
+mod obstruction;
+mod sheaf;
+mod simplex;
+
+pub use cocycle::{Coboundary, Cocycle, CocycleBuilder};
+pub use cohomology_group::{BettiNumbers, CohomologyComputer, CohomologyConfig, CohomologyGroup};
+pub use diffusion::{DiffusionResult, ObstructionIndicator, SheafDiffusion, SheafDiffusionConfig};
+pub use laplacian::{HarmonicRepresentative, LaplacianConfig, LaplacianSpectrum, SheafLaplacian};
+pub use neural::{
+    Activation, CohomologyPooling, PoolingMethod, SheafConvolution, SheafNeuralConfig,
+    SheafNeuralLayer,
+};
+pub use obstruction::{Obstruction, ObstructionDetector, ObstructionReport, ObstructionSeverity};
+pub use sheaf::{LocalSection, Sheaf, SheafBuilder, SheafSection, Stalk};
+pub use simplex::{Chain, Cochain, Simplex, SimplexId, SimplicialComplex};